The Athletic Bilbao midfielder thinks that every team is highly motivated to defeat La Roja and insists that France has recovered from its setback to Sweden
La Roja is widely viewed as the favorites for the tournament, but had some anxious moments in its group matches against Italy and Croatia.
Spain's performances have raised doubts about the chances of defending its European crown, but Martinez stated that the team's recent triumphs give an extra source of motivation to opponents.
"The atmosphere in the team is good," he said during a press conference. "We are very confident, and we knew that we would have some difficult moments.
"Having won Euro 2008 and World Cup 2010 makes things harder for us. Everyone wants to beat us.
"Although we had a complicated group stage, the team is fine and reinforced after these matches."
Looking ahead to the quarterfinal clash against France, Martinez is wary of Les Bleus' attacking threat and played down the fact that they head into Saturday's match on the back of a 2-0 defeat against Sweden.
"I think that France try to control the ball and have very quick attackers, so we will have to be alert at the back," the 23-year-old affirmed.
"The key will be to try to have the ball. We will have to take the ball away from them.
"France's situation is similar to our own because, because both teams played better in the first two group matches than in the third game.
"I am sure they have overcome what happened against Sweden and that they will be very motivated against us."